In a conventional hydraulically operated dockboard, as disclosed in U.S. Pat. No. 4,641,388, a hydraulic cylinder interconnects the frame and the ramp and a lip cylinder interconnects the ramp and the lip. Extension of the ramp cylinder will pivot the ramp upwardly from a horizontal cross traffic position to an upwardly inclined position, while extension of the lip cylinder will pivot the lip from a downwardly hanging pendant position to an extended position where it forms an extension to the ramp.
If the ramp is at a below dock level position when the truck pulls away from the loading dock, the ramp will remain at this downwardly inclined position unless the hydraulic system is manually activated to extend the ramp cylinder and raise the ramp. After the ramp is elevated to a position slightly above horizontal or dock level, the operation of the pump of the hydraulic system is manually terminated and the ramp will then descend by gravity until the cross traffic legs, which depend from the forward edge of the ramp, engage supports on the frame to maintain the ramp in the horizontal or cross traffic position.
It has been found that occasionally the dock operator may not carry out this procedure to return the ramp to a horizontal or dock level position, with the result that the ramp remains in the downwardly inclined position. With the ramp in this below dock level position, it can provide an obstruction to material handling equipment moving over the dock.